The present invention relates to data storage, and more particularly, to methods and systems for a high throughput storage device.
A form of on-line transaction processing (OLTP) applications requiring a high number of data block reads or writes are called H-OLTP applications. A large server or mainframe or several servers typically host an H-OLTP application. Typically, these applications involve the use of a real time operating system, a relational database, optical fiber based networking, distributed communications facilities to a user community, and the application itself. Storage solutions for these applications use a combination of mechanical disk drives and cached memory under stored program control. The techniques for the storage management of H-OLTP applications can use redundant file storage algorithms on multiple disk drives, memory cache replications, data coherency algorithms, and/or load balancing.
A brief overview of the storage management technologies of cached disk arrays (CDAs) and solid-state disk storage systems (SSDs) follows.
Cached disk arrays (CDAs) combine disk drives and solid-state memory systems under common program control. The disk drives in CDAs are servo-mechanical devices. Advances in motor technology currently allow the platters of the disk drives to spin at 15,000 revolutions per minute; advanced systems may spin their platters at 18,000 revolutions per minute.
CDAs combine several racks of rotating disks with a common memory cache in an architecture where capacity may be added through the addition of more racks of devices, more cache, or both. CDAs often are used by companies to provide storage services in their mission critical applications, including H-OLTP applications.
The on-board cache of a CDA stores frequently used data because access times for data in cache memory can be short relative to access times for data on the drives. Such high-end storage system devices with rotating media, such as CDAs, include less than ideally desirable characteristics in terms of total throughput and memory cache size.
A solid-state disk (SSD) is a storage device corresponding to the solid-state memory attached to a computer's central processing unit through its internal bus structure. To an external computer (server or mainframe) the SSD appears as a very fast disk drive when it is directly attached to the computer over a fast communications link or network. Operating under stored program control, SSDs store frequently used information like transaction logs, database indices, and specialized data structures integral to the efficient execution of a company's mission critical applications.
It would be desirable for large capacity storage to provide sufficient throughput for high-volume, real-time applications, especially, for example in emerging applications in financial, defense, research, customer management, and homeland security areas.